Probe and imaging apparatus for diagnosis

ABSTRACT

A probe includes a transmitting and receiving unit in which an ultrasonic wave transmitting and receiving unit and a light transmitting and receiving unit are arranged. The ultrasonic wave transmitting and receiving unit and the light transmitting and receiving unit are arranged along an axial direction. A distance L [mm] between a position of the ultrasonic wave transmitting and receiving unit in the axial direction and a position of the light transmitting and receiving unit in the axial direction, and the angular difference θ [degrees] between a transmit direction of an ultrasonic wave of the ultrasonic wave transmitting and receiving unit and a transmit direction of light of the light transmitting and receiving unit satisfy a relationship of L=V/ω×θ/360 when having a rotary velocity ω [r/s] of the transmitting and receiving unit  221  and a movement velocity V [mm/s] of the transmitting and receiving unit  221  in the axial direction.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a continuation of International Application No.PCT/JP2013/001853 filed on Mar. 19, 2013, and claims priority toJapanese Application No. 2012-069682 filed on Mar. 26, 2012, the entirecontent of both of which is incorporated herein by reference.

TECHNICAL FIELD

The disclosure here generally relates to a probe and an imagingapparatus for diagnosis.

BACKGROUND INFORMATION

Imaging apparatuses for diagnosis have been widely used to performdiagnoses of arteriosclerosis, preoperative diagnoses duringintra-vascular treatment using a high-performance catheter such as aballoon catheter or a stent, and checking postoperative results.

The imaging apparatus for diagnosis includes an intra-vascular ultrasound diagnostic apparatus (IVUS) and an optical coherence tomography(OCT) and the like, each of which has characteristics different fromeach other.

Recently, there has been proposed an imaging apparatus for diagnosis inwhich the function of the IVUS and the function of the OCT are combined(for example, refer to Japanese Patent Application Publication No.11-56752 and Japanese Patent Application Publication No. 2010-508973).According to such an imaging apparatus for diagnosis, it is possible togenerate a tomographic image taking advantage of the IVUS which canmeasure up to a high depth region and an advantage of the OCT which canmeasure an area in high resolution.

SUMMARY

However, generally in an imaging apparatus for diagnosis, a tomographicimage is generated by transmitting and receiving ultrasonic waves orlight in a transmitting and receiving unit while a probe unit performs arotary operation and an axial-direction operation inside a blood vessel.Accordingly, when a transmitting and receiving unit for IVUS and atransmitting and receiving unit for OCT are arranged inside a probe asdisclosed in Japanese Patent Application Publication No. 11-56752 andJapanese Patent Application Publication No. 2010-508973, a deviationoccurs in scanning positions of an ultrasonic wave and light inside ablood vessel. This is because transmitting and receiving positions ofthe transmitting and receiving unit for IVUS and the transmitting andreceiving unit for OCT cannot be completely the same, since each of thetransmitting and receiving unit for IVUS and the transmitting andreceiving unit for OCT has a certain size and both need to be arrangedso as to be misaligned in a radial direction or an axial direction.

Meanwhile, properties of plaque and the like inside a blood vessel canbe effectively observed by using a tomographic image which is generatedthrough the IVUS and a tomographic image which is generated through theOCT. Therefore, when there is any deviation in the scanning position,there is a possibility that the effective observation may not beperformed.

For this reason, in such an imaging apparatus for diagnosis describedabove, it is desirable to match the scanning position inside a bloodvessel which is subject to the scanning by the transmitting andreceiving unit for IVUS and the scanning position inside the bloodvessel which is subject to the scanning by the transmitting andreceiving unit for OCT with each other so as to be able to observecompletely the same position.

The probe disclosed here has been made taking the aforementionedproblems into consideration, and aims to be able to observe the sameposition in an imaging apparatus for diagnosis in which a transmittingand receiving unit which can transceive an ultrasonic wave and atransmitting and receiving unit which can transceive light are used soas to be able to generate each tomographic image.

The probe includes a transmitting and receiving unit in which anultrasonic wave transmitting and receiving unit for transmitting andreceiving an ultrasonic wave and a light transmitting and receiving unitfor transmitting and receiving light are arranged. An ultrasonic waveand light are transmitted while the transmitting and receiving unitrotates. A reflected wave and reflected light can be transferred to animaging apparatus for diagnosis which uses the reflected wave which isreceived by the ultrasonic wave transmitting and receiving unit from abiological tissue and the reflected light which is received by the lighttransmitting and receiving unit from a biological tissue to generate anultrasonic wave tomographic image and a light tomographic image of thebiological tissue in an axial direction, while the probe moves inside abody lumen in the axial direction. The ultrasonic wave transmitting andreceiving unit and the light transmitting and receiving unit arearranged so as to make an angular difference θ [degrees] between theultrasonic wave transmitting and receiving unit and the lighttransmitting and receiving unit in an azimuth angle direction beproportional to a distance L [mm] between a position of the ultrasonicwave transmitting and receiving unit in the axial direction and aposition of the light transmitting and receiving unit in the axialdirection and a rotary velocity ω [r/s] of the transmitting andreceiving unit, and be inversely proportional to a movement velocity V[mm/s] of the transmitting and receiving unit in the axial direction.

It is possible to observe the same position in an imaging apparatus fordiagnosis in which a transmitting and receiving unit which cantransceive an ultrasonic wave and a transmitting and receiving unitwhich can transceive light are used so as to be able to generate eachtomographic image.

Other characteristics and advantages will be obvious in the followingdescription with reference to the accompanying drawings. Regarding theaccompanying drawings, the same reference numerals and signs will beapplied to the same or the similar configurations.

BRIEF DESCRIPTION OF DRAWINGS

The accompanying drawings are incorporated in this specification, takepart in the configuration, and illustrate embodiments of the probe andimaging apparatus, thereby being used to explain the description and theprinciple of the probe and imaging apparatus.

FIG. 1 is a view illustrating an appearance of a configuration of animaging apparatus for diagnosis 100 according to an embodiment.

FIG. 2 is a view illustrating an overall configuration and across-sectional configuration of the distal portion of a probe unit.

FIG. 3 is a view illustrating a cross-sectional configuration of animaging core, and an arrangement of an ultrasonic wave transmitting andreceiving unit and a light transmitting and receiving unit.

FIG. 4A is a view illustrating scanning positions when an ultrasonicwave transmitting and receiving unit and a light transmitting andreceiving unit of an imaging apparatus for diagnosis in the related artare caused to perform a rotary operation and an axial-directionoperation.

FIG. 4B is a view illustrating scanning positions when the ultrasonicwave transmitting and receiving unit and the light transmitting andreceiving unit of the imaging apparatus for diagnosis 100 are caused toperform the rotary operation and the axial-direction operation.

FIG. 5 is a view illustrating a functional configuration of the imagingapparatus for diagnosis 100.

FIG. 6 is a view illustrating a functional configuration of a signalprocessing unit.

FIG. 7 is a view for describing a correspondence relationship between atomographic image generated by the imaging apparatus for diagnosis 100and the scanning positions of the ultrasonic wave transmitting andreceiving unit and the light transmitting and receiving unit.

FIG. 8 is a view for describing a correspondence relationship betweenline data of an ultrasonic wave signal and a light signal generated bythe imaging apparatus for diagnosis 100 and frames.

FIG. 9 is a view illustrating another cross-sectional configuration ofthe imaging core, and another arrangement of the ultrasonic wavetransmitting and receiving unit and the light transmitting and receivingunit.

DETAILED DESCRIPTION

Hereinafter, each embodiment of the probe and imaging apparatusdisclosed here will be described in detail with reference to theaccompanying drawings.

First Embodiment

1. Configuration of Appearance of Imaging Apparatus for Diagnosis

FIG. 1 is a view illustrating an appearance of a configuration of animaging apparatus for diagnosis 100 (imaging apparatus for diagnosisprovided with function of IVUS and function of OCT) according to anembodiment.

As illustrated in FIG. 1, the imaging apparatus for diagnosis 100includes a probe unit 101, a scanner & pull-back unit 102 and anoperation control apparatus 103. The scanner & pull-back unit 102 andthe operation control apparatus 103 are connected to each other througha signal wire 104 so as to be able to transfer various signals.

An imaging core which is directly inserted into a body cavity such as ablood vessel is interpolated into the probe unit 101. The imaging coreincludes an ultrasonic wave transmitting and receiving unit whichtransmits an ultrasonic wave based on a pulse signal to the inside of abody cavity and receives a reflected wave from the inside of a bodycavity, and a light transmitting and receiving unit which continuouslytransmits transferred light (measurement light) to the inside of a bodycavity and continuously receives a reflected light from the inside of abody cavity. In the imaging apparatus for diagnosis 100, the imagingcore is used to measure a state inside a body cavity.

The probe unit 101 is detachably attached to the scanner & pull-backunit 102 which regulates the imaging core interpolated into the probeunit 101 regarding an operation in an axial direction and an operationin a rotary direction inside a body cavity by driving a built-in motor.The scanner & pull-back unit 102 acquires the reflected wave received bythe ultrasonic wave transmitting and receiving unit and the reflectedlight received by the light transmitting and receiving unit, therebyperforming transmission to the operation control apparatus 103.

The operation control apparatus 103 includes a function for inputtingvarious setting values when performing the measurement, and a functionfor processing data obtained through measurement and displaying it as atomographic image inside a body cavity.

In the operation control apparatus 103, the reference numeral 111indicates a main body control unit, which generates ultrasonic wave databased on a reflected wave obtained through the measurement, andprocesses line data generated based on the ultrasonic wave data, therebygenerating an ultrasonic wave tomographic image. The main body controlunit 111 generates interference light data by causing reflected lightobtained through the measurement and reference light obtained byseparating light from a light source to interfere with each other, andprocesses the line data generated based on the interference light data,thereby generating a light tomographic image.

The reference numeral 111-1 indicates a printer & DVD recorder, whichprints a processing result of the main body control unit 111 or storesthe same as data. The reference numeral 112 indicates an operationpanel, and a user inputs various setting values and instructions via theoperation panel 112. The reference numeral 113 indicates an LCD monitoras a display device, which displays tomographic images generated in themain body control unit 111.

2. Overall Configuration of Probe Unit and Cross-Sectional Configurationof Distal Portion of the Probe Unit

Subsequently, an overall configuration of the probe unit 101 and across-sectional configuration of the distal portion of the probe unit101 will be described using FIG. 2. As illustrated in FIG. 2, the probeunit 101 is configured to include an elongated catheter sheath 201 whichis inserted into a body cavity such as a blood vessel, and a connectorunit 202 which is arranged on a hand side of a user to be manipulated bythe user without being inserted into a body cavity such as a bloodvessel. A guide wire lumen tube 203 configuring a guide wire lumen isprovided at a distal end of the catheter sheath 201. That is, The distalend of the catheter sheath 201 includes a tube 203 possessing a guidewire lumen configured to receive a guide wire. The catheter sheath 201forms a lumen leading from a portion connected to the guide wire lumentube 203 to a portion connected to the connector unit 202.

Inside a lumen of the catheter sheath 201, an imaging core 220 includinga transmitting and receiving unit 221 and a coil-shaped drive shaft 222is inserted through the catheter sheath 201 throughout substantially theoverall length of the catheter sheath 201. In the transmitting andreceiving unit 221, the ultrasonic wave transmitting and receiving unitfor transmitting and receiving an ultrasonic wave and the lighttransmitting and receiving unit for transmitting and receiving light arearranged. The drive shaft 222 is internally provided with an electricsignal cable and an optical fiber cable and transfers a rotary driveforce for rotating the ultrasonic wave transmitting and receiving unitand the light transmitting and receiving unit.

The connector unit 202 includes a sheath connector 202 a which isconfigured to be unified to a proximal end of the catheter sheath 201,and a drive shaft connector 202 b which is configured to rotatably fixthe drive shaft 222 at a proximal end of the drive shaft 222.

In a boundary portion between the sheath connector 202 a and thecatheter sheath 201, an anti-kink protector 211 is provided.Accordingly, a predetermined rigidity is maintained and bending (kink)due to a rapid change of physical properties can be prevented.

A proximal end of the drive shaft connector 202 b is detachably attachedto the scanner & pull-back unit 102.

Subsequently, a cross-sectional configuration of a distal portion of theprobe unit 101 will be described. Inside the lumen of the cathetersheath 201, the imaging core 220 including a housing 223 and the driveshaft 222 is inserted through throughout substantially the overalllength of the catheter sheath 201, thereby forming the probe unit 101.In the housing 223, there is provided the transmitting and receivingunit 221 in which the ultrasonic wave transmitting and receiving unitfor transmitting and receiving an ultrasonic wave and the lighttransmitting and receiving unit for transmitting and receiving light arearranged. The drive shaft 222 transfers a rotary drive force forrotating the ultrasonic wave transmitting and receiving unit and thelight transmitting and receiving unit.

The transmitting and receiving unit 221 transmits an ultrasonic wave andlight toward a tissue inside a body cavity and receives a reflected waveand reflected light from a tissue inside a body cavity.

The drive shaft 222 is in a coil shape, with the electric signal cableand the optical fiber cable (single mode optical fiber cable) providedinside the drive shaft 222.

The housing 223 is a metallic pipe having a short cylindrical shape inwhich a notch portion is provided in a portion. The housing 223 isformed through carving from metal ingots, metal powder injection molding(MIM) and the like. The housing 223 internally has the ultrasonic wavetransmitting and receiving unit and the light transmitting and receivingunit as the transmitting and receiving unit 221, and a proximal side ofthe transmitting and receiving unit 221 is connected to the drive shaft222. A short coil-shaped elastic member 231 is provided on a distal sideof the transmitting and receiving unit 221.

The elastic member 231 is a stainless steel wire formed to have a coilshape, and the elastic member 231 is disposed on the distal side so asto be prevented from being caught inside the catheter sheath 201 whenthe imaging core 220 moves back and forth.

The reference numeral 232 indicates a reinforcement coil which isprovided for the purpose of preventing a drastic bend of a distalportion of the catheter sheath 201.

The guide wire lumen tube 203 has a lumen for a guide wire into which aguide wire can be inserted. The guide wire lumen tube 203 receives aguide wire which is inserted into a body cavity such as a blood vesselin advance, thereby being used for guiding the catheter sheath 201 to atarget lesion through the guide wire.

The drive shaft 222 is configured with a multiplex-multilayer bondingcoil and the like made with a metal wire, for example, stainless steelhaving characteristics of being able to cause the transmitting andreceiving unit 221 to perform a rotary operation and an axial operationwith respect to the catheter sheath 201, being soft, and favorablytransferring rotations.

3. Cross-Sectional Configuration of Imaging Core

Subsequently, a cross-sectional configuration of the imaging core 220and an arrangement of the ultrasonic wave transmitting and receivingunit and the light transmitting and receiving unit will be described.FIG. 3 is a view illustrating the cross-sectional configuration of theimaging core, and the arrangement of the ultrasonic wave transmittingand receiving unit and the light transmitting and receiving unit.

As illustrated in 30 a of FIG. 3, the transmitting and receiving unit221 which is disposed inside the housing 223 includes an ultrasonic wavetransmitting and receiving unit 310 and a light transmitting andreceiving unit 320. The ultrasonic wave transmitting and receiving unit310 and the light transmitting and receiving unit 320 are respectivelyarranged on a rotary center axis (on a dot and dash line in 30 a) of thedrive shaft 222 along the axial direction.

The ultrasonic wave transmitting and receiving unit 310 of thetransmitting and receiving unit 221 is arranged on the distal side ofthe probe unit 101, and the light transmitting and receiving unit 320 isarranged on the proximal side of the probe unit 101. The ultrasonic wavetransmitting and receiving unit 310 and the light transmitting andreceiving unit 320 are installed in the housing 223 so as to make adistance L (distance gap) between an ultrasonic wave transmitting andreceiving position of the ultrasonic wave transmitting and receivingunit 310 and a light transmitting and receiving position of the lighttransmitting and receiving unit 320.

The ultrasonic wave transmitting and receiving unit 310 and the lighttransmitting and receiving unit 320 are installed in the housing 223 soas to make an ultrasonic wave transmit direction (elevation angledirection) of the ultrasonic wave transmitting and receiving unit 310and a light transmit direction (elevation angle direction) of the lighttransmitting and receiving unit 320 respectively and substantially 90°with respect to the axial direction of the drive shaft 222. It isdesirable for each transmit direction to be slightly misaligned from 90°so as not to receive a reflection of the catheter sheath 201 on theinternal surface of a lumen.

Inside the drive shaft 222, an electric signal cable 311 which isconnected to the ultrasonic wave transmitting and receiving unit 310 andan optical fiber cable 321 which is connected to the light transmittingand receiving unit 320 are disposed. The electric signal cable 311 iswound in a spiral shape with respect to the optical fiber cable 321.

The reference numeral-sign 30 b in FIG. 3 is a cross-sectional view whencut on a plane which is substantially orthogonal to the rotary centeraxis in the ultrasonic wave transmitting and receiving position. Asillustrated in 30 b of FIG. 3, when the downward direction of paper isset to zero, the ultrasonic wave transmit direction (rotary angledirection (also referred to as azimuth angle direction)) of theultrasonic wave transmitting and receiving unit 310 becomes θ.

The reference numeral-sign 30 c in FIG. 3 is a cross-sectional view whencut on a plane which is substantially orthogonal to the rotary centeraxis in the light transmitting and receiving position. As illustrated in30 c of FIG. 3, when the downward direction of paper is set to zero, thelight transmit direction (rotary angle direction) of the lighttransmitting and receiving unit 320 becomes zero. That is, theultrasonic wave transmitting and receiving unit 310 and the lighttransmitting and receiving unit 320 are arranged so as to cause theultrasonic wave transmit direction (rotary angle direction) of theultrasonic wave transmitting and receiving unit 310 and the lighttransmit direction (rotary angle direction) of the light transmittingand receiving unit 320 to be mutually misaligned by θ.

4. Positional Relationship Between Ultrasonic Wave Transmitting andReceiving Unit and Light Transmitting and Receiving Unit

A positional relationship between the ultrasonic wave transmitting andreceiving unit 310 and the light transmitting and receiving unit 320will be further described in detail. As described above, the ultrasonicwave transmitting and receiving unit 310 and the light transmitting andreceiving unit 320 are arranged so that the distance between theultrasonic wave transmitting and receiving position and the lighttransmitting and receiving position on the rotary center axis along theaxial direction is L, and are arranged so that an angular differencebetween the ultrasonic wave transmit direction (rotary angle direction)and the light transmit direction (rotary angle direction) is θ. Theultrasonic wave transmitting and receiving unit 310 and the lighttransmitting and receiving unit 320 are arranged on the same axis (onrotary center axis) in order to match the image center of the ultrasonicwave tomographic image and the image center of the light tomographicimage which are to be constructed.

Here, the distance L and the angular difference θ have the followingrelationship in order to match a scanning position by the ultrasonicwave transmitting and receiving unit 310 and a scanning position by thelight transmitting and receiving unit 320, when a pullback velocity(movement velocity in axial direction) is V_(PB) [mm/s] and a rotaryvelocity is ω [r/s] in the scanner & pull-back unit 102 of the imagingapparatus for diagnosis 100 of the present embodiment.L [mm]=V _(PB) [mm/s]/ω[r/s]×θ[degrees]/360 [degrees]  (Expression 1)

Here, as an example, appropriate values of the distance L and theangular difference θ will be examined below when the pullback velocityV_(PB) is 20 [mm/s] and the rotary velocity ω is 30 [r/s] (1,800 [rpm])of the scanner & pull-back unit 102.

(1) When Considering Simultaneity

The scanning position by the ultrasonic wave transmitting and receivingunit 310 and the scanning position by the light transmitting andreceiving unit 320 can match each other by satisfying Expression 1above. However, it is not desirable for a scanning timing by theultrasonic wave transmitting and receiving unit 310 and a scanningtiming by the light transmitting and receiving unit 320 to be far apartfrom each other. This is because when a deviation (differential time)between the scanning timings is significant, the measurement subject maychange during the measurement.

Therefore, in the imaging apparatus for diagnosis 100 of the presentembodiment, the deviation (differential time) between the scanningtiming by the ultrasonic wave transmitting and receiving unit 310 andthe scanning timing by the light transmitting and receiving unit 320with respect to the same scanning position is caused to be less than 1frame, thereby being configured to enhance the simultaneity of both. Inother words, the imaging apparatus for diagnosis 100 of the presentembodiment is configured to be θ<360° (that is, to be L [mm]<V_(PB)[mm/s]/ω [r/s]).

(2) When Considering Pulsation

When generating a tomographic image inside a blood vessel, there is aneed to consider influence of a pulsation, and it is necessary tosuppress changes inside a blood vessel due to a pulsation during thedifferential time between the scanning timing by the ultrasonic wavetransmitting and receiving unit 310 and the scanning timing by the lighttransmitting and receiving unit 320 with respect to the same scanningposition as much as possible. Generally, when the deviation(differential time) between the scanning timings is suppressed to beequal to or less than 10 msec, the changes inside a blood vessel due toa pulsation can be ignored (when equal to or less than 10 msec, theultrasonic wave transmitting and receiving unit 310 and the lighttransmitting and receiving unit 320 can be considered as performing thescanning at substantially the same timing).

Based on the facts above, in the imaging apparatus for diagnosis 100 ofthe present embodiment, the deviation (differential time) between thescanning timing by the ultrasonic wave transmitting and receiving unit310 and the scanning timing by the light transmitting and receiving unit320 with respect to the same scanning position is suppressed to be equalto or less than 10 msec, and is thereby configured to enhance thesimultaneity of both with respect to a pulsation. In other words, theimaging apparatus for diagnosis 100 of the present embodiment isconfigured to be θ<108° (=10 [msec]/33.3 [msec/r]×360 [degrees]).

(3) When Considering Size of Transmitting and Receiving Unit

The probe unit 101 is directly inserted into a body cavity such as ablood vessel so that there is a need to suppress a length of thetransmitting and receiving unit 221 in the axial direction to be lessthan 600 [μm], and desirably to be approximately 500 [μm], from aviewpoint of low aggressiveness and in consideration of insertion into asmall diameter blood vessel. When considering the manufacturable minimumsize of the ultrasonic wave transmitting and receiving unit 310 and thelight transmitting and receiving unit 320, it is desirably to suppressthe distance L to be equal to or less than 150 [μm].

Based on the facts above, the imaging apparatus for diagnosis 100 of thepresent embodiment is configured to be θ≤90° (=150 [μm]/20 [mm/s]/30[r/s]×360 [degrees]).

5. Description for Scanning Position

On account of the above-described positional relationship between theultrasonic wave transmitting and receiving unit 310 and the lighttransmitting and receiving unit 320, in the imaging apparatus fordiagnosis 100 of the present embodiment, it is possible to perform thescanning of the same scanning position. Hereinafter, using FIGS. 4A and4B, a relationship between the scanning position of the ultrasonic wavetransmitting and receiving unit 310 and the scanning position of thelight transmitting and receiving unit 320 will be described.

For comparison, FIG. 4A illustrates a relationship of scanning positionswhen an ultrasonic wave transmitting and receiving unit and a lighttransmitting and receiving unit of an imaging apparatus for diagnosis inthe related art are caused to perform the rotary operation and theaxial-direction operation (relationship of scanning positions whendistance L and angular difference θ are not defined so as to makeultrasonic wave transmitting and receiving unit and light transmittingand receiving unit perform scanning of same scanning position).

In reference numeral-signs 40 a to 40 c of FIG. 4A, a horizontal axisindicates positional coordinates of a body cavity such as a blood vesselin the axial direction, and a vertical axis indicates positionalcoordinates of a body cavity such as a blood vessel in a radialdirection, respectively.

The reference numeral-sign 40 a indicates a scanning track of theultrasonic wave transmitting and receiving unit, and the referencenumeral-sign 40 b indicates a scanning track of the light transmittingand receiving unit, respectively.

The example of FIG. 4A illustrates an arrangement in which the angulardifference θ between the ultrasonic wave transmit direction (rotaryangle direction) of the ultrasonic wave transmitting and receiving unitand the light transmit direction (rotary angle direction) of the lighttransmitting and receiving unit is 0°, and the distance L between theultrasonic wave transmitting and receiving position and the lighttransmitting and receiving position on the rotary center axis along theaxial direction is L1.

In this case, when the transmitting and receiving unit is caused toperform the rotary operation and the axial-direction operation, asillustrated in 40 c of FIG. 4A, the scanning track of the ultrasonicwave transmitting and receiving unit and the scanning track of the lighttransmitting and receiving unit are misaligned from each other (that is,scanning position of ultrasonic wave transmitting and receiving unit andscanning position of light transmitting and receiving unit are not thesame).

Meanwhile, FIG. 4B illustrates a relationship of scanning positions whenthe ultrasonic wave transmitting and receiving unit 310 and the lighttransmitting and receiving unit 320 are caused to have the relationshipof Expression (1) above.

The example in FIG. 4B illustrates an arrangement in which the angulardifference θ between the ultrasonic wave transmit direction (rotaryangle direction) of the ultrasonic wave transmitting and receiving unitand the light transmit direction (rotary angle direction) of the lighttransmitting and receiving unit is θ2, and the distance L between theultrasonic wave transmitting and receiving position and the lighttransmitting and receiving position on the rotary center axis along theaxial direction is L2.

In this case, when the transmitting and receiving unit 221 is caused toperform the rotary operation and the axial-direction operation, asillustrated in 41 c of FIG. 4B, the scanning track of the ultrasonicwave transmitting and receiving unit 310 and the scanning track of thelight transmitting and receiving unit 320 match each other (that is,scanning position of ultrasonic wave transmitting and receiving unit 310and scanning position of light transmitting and receiving unit 320 arethe same).

6. Functional Configuration of Imaging Apparatus for Diagnosis

Subsequently, a functional configuration of the imaging apparatus fordiagnosis 100 will be described. FIG. 5 is a view illustrating afunctional configuration of the imaging apparatus for diagnosis 100 inwhich a function of IVUS and a function of OCT (herein, wavelengthsweep-type OCT, for example) are combined. An imaging apparatus fordiagnosis in which a function of IVUS and a function of other type ofOCT are combined also has a similar functional configuration. Thedescription of such a configuration is not repeated.

(1) Function of IVUS

The imaging core 220 includes the ultrasonic wave transmitting andreceiving unit 310 inside the distal end of the imaging core 220. Theultrasonic wave transmitting and receiving unit 310 transmits anultrasonic wave to a biological tissue based on a pulse wave transmittedfrom an ultrasonic wave signal transmitting and receiving unit 552,receives a reflected wave (echo) of the transmitted ultrasonic wave, andtransmits the reflected wave to the ultrasonic wave signal transmittingand receiving unit 552 as an ultrasonic wave echo via an adaptor 502 anda slip ring 551.

A rotary drive portion side of the slip ring 551 is rotationally drivenby a radial scanning motor 505 of a rotary drive apparatus 504. A rotaryangle of the radial scanning motor 505 is detected by an encoder unit506. The scanner & pull-back unit 102 includes a linear drive apparatus507 and defines the axial-direction operation of the imaging core 220based on a signal from a signal processing unit 528.

The ultrasonic wave signal transmitting and receiving unit 552 includesa transmit wave circuit and a reception wave circuit (not illustrated).The transmit wave circuit transmits a pulse wave to the ultrasonic wavetransmitting and receiving unit 310 inside the imaging core 220 based ona control signal transmitted from the signal processing unit 528.

The reception wave circuit receives an ultrasonic wave signal from theultrasonic wave transmitting and receiving unit 310 inside the imagingcore 220. The received ultrasonic wave signal is input to a wavedetector 554 after being amplified by an amplifier 553, therebyperforming wave-detecting.

In an A/D converter 555, ultrasonic wave signals output from the wavedetector 554 are sampled at as many as 200 points at 30.6 MHz, therebygenerating digital data (ultrasonic wave data) of 1 line. The frequencyis set to 30.6 MHz herein on a premise that 200 points are to be sampledwith respect to the depth of 5 mm when the sound velocity is consideredto be 1,530 m/sec. Therefore, the sampling frequency is not particularlylimited thereto.

The ultrasonic wave data in a line unit generated in the A/D converter555 is input to the signal processing unit 528. In the signal processingunit 528, the ultrasonic wave data is converted into a gray scale so asto form the ultrasonic wave tomographic image in each position inside abody cavity such as a blood vessel, thereby outputting the ultrasonicwave tomographic image to the LCD monitor 113 at a predetermined framerate.

The signal processing unit 528 is connected to a motor control circuit529, thereby receiving a video synchronization signal of the motorcontrol circuit 529. In the signal processing unit 528, the ultrasonicwave tomographic image is constructed being synchronized with thereceived video synchronization signal.

The video synchronization signal of the motor control circuit 529 isalso transmitted to the rotary drive apparatus 504, and the rotary driveapparatus 504 outputs a drive signal which is synchronized with thevideo synchronization signal.

(2) Function of Wavelength Sweep-Type OCT

The reference numeral 508 indicates a wavelength swept light source(swept laser), and it is a type of an extended-cavity laser which isconfigured to have an optical fiber 516 which is coupled with asemiconductor optical amplifier 515 (SOA) in a ring shape, and a polygonscanning filter (508 b).

Light output from the SOA 515 proceeds through the optical fiber 516 andis input to the polygon scanning filter 508 b. The light is subjected towavelength selection herein, is amplified in the SOA 515, and lastly, isoutput from a coupler 514.

In the polygon scanning filter 508 b, the wavelength is selected bycombining a diffraction grating 512 which disperses light, and a polygonmirror 509. Specifically, rays of light dispersed by the diffractiongrating 512 are concentrated on a surface of the polygon mirror 509 byusing two lenses (510, 511). Accordingly, only the light having awavelength which is orthogonal to the polygon mirror 509 returns thesame optical path, thereby being output from the polygon scanning filter508 b. In other words, time sweep of a wavelength can be performed byrotating the polygon mirror 509.

In the polygon mirror 509, for example, a 32-hedron mirror is used andthe number of rotations is approximately 50,000 rpm. High speed and highoutput wavelength sweep can be performed through the wavelength sweepmethod in which the polygon mirror 509 and the diffraction grating 512are combined.

Light of the wavelength swept light source 508 which is output from thecoupler 514 is incident on an end of a first single mode fiber 540,thereby being transmitted to the distal side of the first single modefiber 540. The first single mode fiber 540 is optically coupled to asecond single mode fiber 545 and a third single mode fiber 544 in anphoto coupler unit 541 which is between the second single mode fiber 545and the third single mode fiber 544. Therefore, light incident on thefirst single mode fiber 540 is divided into three optical paths at themaximum by the photo coupler unit 541, thereby being transmitted.

On a further distal side than the photo coupler unit 541 of the firstsingle mode fiber 540, an optical rotary joint (optical couplingportion) 503 which connects a non-rotary portion (fixing portion) and arotary portion (rotary drive portion) with each other and transferslight is provided inside the rotary drive apparatus 504.

On a distal side of a fourth single mode fiber 542 inside the opticalrotary joint (optical coupling portion) 503, a fifth single mode fiber543 of the probe unit 101 is freely and detachably connected via theadaptor 502. Accordingly, light from the wavelength swept light source508 is transferred to the fifth single mode fiber 543 which is insertedthrough the imaging core 220 to be rotatably driven.

Emission of transferred light is performed while being subjected to therotary operation and the axial-direction operation from the lighttransmitting and receiving unit 320 of the imaging core 220 to abiological tissue inside a body lumen. A portion of reflected lightscattered in the inside or on a surface of a biological tissue iscollected by the light transmitting and receiving unit 320 of theimaging core 220, thereby returning to the first single mode fiber 540side via an optical path in reverse. The portion of the reflected lightmoves to the second single mode fiber 545 side by the photo coupler unit541, and the light is received by the light detector (for example,photo-diode 524) after being emitted from an end of the second singlemode fiber 545.

The rotary drive portion side of the optical rotary joint 503 isrotationally driven by the radial scanning motor 505 of the rotary driveapparatus 504. A rotary angle of the radial scanning motor 505 isdetected by the encoder unit 506. The scanner & pull-back unit 102includes the linear drive apparatus 507 and defines the axial-directionoperation of the imaging core 220 based on an instruction from thesignal processing unit 528.

Meanwhile, an optical path length varying mechanism 532 forfine-adjusting the optical path length of the reference light isprovided in a distal end on a side opposite to the photo coupler unit541 of the third single mode fiber 544.

The optical path length varying mechanism 532 includes optical pathlength changing means for changing the optical path length correspondingto a fluctuation in a length of each probe unit 101 so as to be able toabsorb the fluctuation in the length of each probe unit 101 when theprobe unit 101 is replaced and used.

The third single mode fiber 544 and a collimating lens 518 are providedon a one-axis stage 522 which is movable in an optical-axis direction asindicated by the arrow 523, thereby forming the optical path lengthchanging means.

Specifically, the one-axis stage 522 functions as the optical pathlength changing means having a movable range of the optical path lengthas wide as the fluctuation in the optical path length of the probe unit101 can be absorbed when the probe unit 101 is replaced. The one-axisstage 522 also includes a function as adjustment means for adjusting anoffset. For example, when the distal end of the probe unit 101 is not inclose contact with a surface of a biological tissue, it is possible toset a state of being interfered with the reflected light from thesurface position of the biological tissue by minutely changing theoptical path length through the one-axis stage.

The optical path length is fine-adjusted in the one-axis stage 522, andlight reflected by the mirror 521 via a grating 519 and a lens 520 ismixed with light acquired from the first single mode fiber 540 side inthe photo coupler unit 541 which is provided in an intermediate portionof the third single mode fiber 544, and thus, the light is received inthe photo-diode 524.

The interference light received in the photo-diode 524 in such a manneris subjected to photoelectric conversion, thereby being input to ademodulator 526 after being amplified by the amplifier 525. In thedemodulator 526, demodulation processing in which only the signalportion is extracted from the interfered light is performed, and theoutput is input to an A/D converter 527 as an interference light signal.

In the A/D converter 527, an interference light signal is sampled, forexample, at as many as 2,048 points at 180 MHz, thereby generatingdigital data (interference light data) of 1 line. The sampling frequencyis set to 180 MHz on a premise that approximately 90% of a periodicalcycle (12.5 μsec) of the wavelength sweep is extracted as digital dataof 2,048 points when a repetition frequency of the wavelength sweep isset to 40 kHz, without being particularly limited thereto.

The interference light data in a line unit generated in the A/Dconverter 527 is input to the signal processing unit 528. When in ameasurement mode, the interference light data is subjected to frequencyresolution through fast Fourier transform (FFT) in the signal processingunit 528 so as to generate data in a depth direction (line data). Theline data is subjected to coordinate-conversion to construct a lighttomographic image in each position inside a body cavity such as a bloodvessel, thereby being output to the LCD monitor 113 at a predeterminedframe rate.

The signal processing unit 528 is further connected to an optical pathlength adjustment means control device 530. The signal processing unit528 controls a position of the one-axis stage 522 via the optical pathlength adjustment means control device 530.

7. Functional Configuration of Signal Processing Unit

Subsequently, in the signal processing unit 528 of the imaging apparatusfor diagnosis 100, a functional configuration of the signal processingunit 528 for constructing a tomographic image will be described withreference to FIG. 6. The construction processing described below may berealized using an exclusive hardware, or may be realized using asoftware (through execution of program by computer).

FIG. 6 is a view illustrating a functional configuration and functionalblocks related thereto for realizing the construction processing in thesignal processing unit 528 of the imaging apparatus for diagnosis 100.

As illustrated in FIG. 6, the interference light data 621 generated inthe A/D converter 527 is processed so as to have the number of lines perone rotation in the radial scanning become 512 in a line data generationportion 601 inside the signal processing unit 528, using a signal of theencoder unit 506 of the radial scanning motor 505 which is output fromthe motor control circuit 529.

Herein, as an example, the light tomographic image is constructed with512 lines. However, the construction is not limited to the number of thelines.

Line data 622 which is output from the line data generation portion 601is stored in a line data memory 602 for one rotation of the radialscanning based on an instruction from a control unit 605. In this case,in the control unit 605, pulse signals 641 which are output from amovement amount detector of the linear drive apparatus 507 are countedso as to be stored while the count value at the time the line data 622is individually generated corresponds to the counted pulse signals 641when the line data 622 is stored in the line data memory 602.

Stored line data 623 corresponding to the count value is subjected to Rθconversion after performing various processing (line addition-averagingprocessing, filtering processing and the like) in a light tomographicimage construction unit 603 based on an instruction from the controlunit 605, thereby being sequentially output as the light tomographicimage 624.

In an image processing unit 604, after performing the image processingto be displayed on the LCD monitor 113, the line data 623 is output tothe LCD monitor 113 as the light tomographic image 625.

Similarly, ultrasonic wave data 631 generated in the A/D converter 555is processed so as to have the number of lines per one rotation in theradial scanning become 512 in a line data generating unit 611 inside thesignal processing unit 528, using a signal of the encoder unit 506 ofthe radial scanning motor 505 which is output from the motor controlcircuit 529.

Line data 632 which is output from the line data generating unit 611 isstored in a line data memory 612 for one rotation of the radial scanningbased on an instruction from the control unit 605. In this case, in thecontrol unit 605, pulse signals 641 which are output from the movementamount detector of the linear drive apparatus 507 are counted so as tobe stored while the count value at the time the line data 632 isindividually generated corresponds to the counted pulse signals 641 whenthe line data 632 is stored in the line data memory 612.

The count value to be stored while corresponding to the line data 632which is stored for one rotation of the radial scanning is misalignedwith the count value to be stored while corresponding to the line data622 which is stored for one rotation of the radial scanning by the countvalue corresponding to the angular difference θ between the ultrasonicwave transmit direction (rotary angle direction) and the light transmitdirection (rotary angle direction). Description will be given in detailwith reference to FIGS. 7 and 8.

FIG. 7 is a view for describing a correspondence relationship betweenthe ultrasonic wave tomographic image and the light tomographic imagegenerated by the imaging apparatus for diagnosis 100, and the scanningpositions of the ultrasonic wave transmitting and receiving unit 310 andthe light transmitting and receiving unit 320. FIG. 8 is a view fordescribing a correspondence relationship between the line data 632 ofthe ultrasonic wave data and the line data 622 of the interference lightdata generated by the imaging apparatus for diagnosis 100, and frames.

In the reference numeral-signs 70 a and 70 b of FIG. 7, the horizontalaxis indicates time, and the vertical axis indicates positionalcoordinates of a body cavity such as a blood vessel in a radialdirection, respectively. The reference numeral-sign 70 a indicates thescanning track of the ultrasonic wave transmitting and receiving unit310, and the reference numeral-sign 70 b indicates a scanning track ofthe light transmitting and receiving unit 320, respectively.

As described above, since the ultrasonic wave transmit direction (rotaryangle direction) and the light transmit direction (rotary angledirection) have an angular difference θ, when the radial scanning isstarted simultaneously, the scanning position of the ultrasonic wavetransmitting and receiving unit 310 and the scanning position of thelight transmitting and receiving unit 320 become different from eachother each time (for example, at the time the radial scanning starts,the ultrasonic wave transmitting and receiving unit 310 performs thescanning of the scanning position indicated by the reference numeral701, and to the contrary, the light transmitting and receiving unit 320performs scanning of the scanning position indicated by the referencenumeral 711).

Therefore, when the line data 632 for one frame of the ultrasonic wavetomographic image and the line data 622 for one frame of the lighttomographic image are configured to be taken at the same timing, each ofthe tomographic images are constructed using the line data of thescanning positions which are different from each other.

Accordingly, based on the differential time as much as the angulardifference between the ultrasonic wave transmit direction (rotary angledirection) and the light transmit direction (rotary angle direction),the imaging apparatus for diagnosis 100 of the present embodiment isconfigured to take the line data for one rotation of the radialscanning.

For example, an ultrasonic wave tomographic image 702 is an ultrasonicwave tomographic image which is constructed by storing the line dataacquired at the timing 703 as the first line data for one rotation ofthe radial scanning, and storing the line data acquired at the timing704 as the 512th line data for one rotation of the radial scanning.

Meanwhile, a light tomographic image 712 is a light tomographic imagewhich is constructed by storing the line data acquired at the timing 711as the first line data for one rotation of the radial scanning, andstoring the line data acquired at the timing 714 as the 512th line datafor one rotation of the radial scanning.

The reference numeral-sign 80 a of FIG. 8 is a view illustrating anexample of the line data 632 stored in the line data memory 612 in amanner described above, and the reference numeral-sign 80 b of FIG. 8 isa view illustrating an example of the line data 622 stored in the linedata memory 602.

As learned from the comparison between 80 a in FIGS. 8 and 80 b in FIG.8, the line data 632 for one rotation of the radial scanning and theline data 622 for one rotation of the radial scanning are stored in theline data memory 612 while being misaligned from each other by angulardifference θ.

Description returns to FIG. 6. Stored line data 633 corresponding to thecount value is subjected to Rθ conversion after performing variousprocessing (line addition-averaging processing, filtering processing andthe like) in a ultrasonic wave tomographic image construction unit 613based on an instruction from the control unit 605, thereby beingsequentially output as the ultrasonic wave tomographic image 634.

In the image processing unit 604, after performing the image processingto be displayed on the LCD monitor 113, the line data 633 is output tothe LCD monitor 113 as the ultrasonic wave tomographic image 635.

As it is obvious from the description above, in the imaging apparatusfor diagnosis 100 of the present embodiment, when being arranged on therotary center axis along the axial direction, the ultrasonic wavetransmitting and receiving unit 310 and the light transmitting andreceiving unit 320 are arranged to correspond to the pullback velocityand the rotary velocity in the scanner & pull-back unit.

The distance between the ultrasonic wave transmitting and receiving unit310 and the light transmitting and receiving unit 320 and the angulardifference in the rotary angle direction are configured to be determinedin consideration of the simultaneity in measurement and influence of apulsation therebetween and the size of the transmitting and receivingunit.

The line data used for constructing one frame of the ultrasonic wavetomographic image and the line data used for constructing one frame ofthe light tomographic image are configured to be determined inaccordance with the angular difference between the ultrasonic wavetransmitting and receiving unit 310 and the light transmitting andreceiving unit 320 in the rotary angle direction.

As a result, it is possible to observe the same position in an imagingapparatus for diagnosis in which the ultrasonic wave transmitting andreceiving unit and the light transmitting and receiving unit are used tobe able to respectively generate the tomographic images.

Second Embodiment

In the first embodiment, the ultrasonic wave transmitting and receivingunit 310 and the light transmitting and receiving unit 320 areconfigured to be arranged on the rotary center axis along the axialdirection. However, the probe unit disclosed here is not limited to theabove configuration. The ultrasonic wave transmitting and receiving unit310 and the light transmitting and receiving unit 320 may be configuredto be misaligned from the rotary center axis. This is because each ofthe image centers can be adjusted through the image processing whengenerating the ultrasonic wave image and when generating the lighttomographic image. Therefore, the ultrasonic wave transmitting andreceiving unit 310 and the light transmitting and receiving unit 320 arenot necessarily arranged on the rotary center axis.

FIG. 9 is a view illustrating another cross-sectional configuration ofthe imaging core, and another arrangement of the ultrasonic wavetransmitting and receiving unit and the light transmitting and receivingunit in the imaging apparatus for diagnosis of the present embodiment.Herein, the description will be given focusing on the dissimilarity withFIG. 3.

As illustrated in FIG. 9, in the imaging apparatus for diagnosis of thepresent embodiment, the ultrasonic wave transmitting and receiving unit310 and the light transmitting and receiving unit 320 are arranged inpositions apart from the rotary center axis by distance r, and arrangedto cause the angular difference between the ultrasonic wave transmitdirection (rotary angle direction) and the light transmit direction(rotary angle direction) to be θ.

In this manner, the ultrasonic wave transmitting and receiving unit andthe light transmitting and receiving unit can observe the same positionby being configured to be respectively arranged in positions atequivalent distances from the rotary center axis along the axialdirection, similar to the first embodiment.

Third Embodiment

In the first embodiment, the ultrasonic wave transmitting and receivingunit 310 is arranged on the distal side and the light transmitting andreceiving unit 320 is arranged on the proximal side in theconfiguration. However, the probe unit disclosed here is not limited inthis particular configuration. The light transmitting and receiving unit320 may be arranged on the distal side of the probe unit 101 and theultrasonic wave transmitting and receiving unit 310 may be arranged onthe proximal side of the probe unit 101 in the configuration.

In the first embodiment, there is no particular mention regarding anaspect of displaying the constructed ultrasonic wave tomographic imageand light tomographic image. However, the ultrasonic wave tomographicimage and the light tomographic image may be configured to display thetomographic images which respectively correspond to the positions insidea body cavity such as a blood vessel in the axial direction in parallel,or may be configured to display the same to overlap with each other soas to match the image centers.

The detailed description above describes embodiments of a probe unit andimaging apparatus representing examples of the probe unit and imagingapparatus of the present invention. The invention is not limited,however, to the precise embodiments and variations described. Variouschanges, modifications and equivalents can be effected by one skilled inthe art without departing from the spirit and scope of the invention asdefined in the accompanying claims. It is expressly intended that allsuch changes, modifications and equivalents which fall within the scopeof the claims are embraced by the claims.

What is claimed is:
 1. A probe comprising: a transmitting and receivingunit in which an ultrasonic wave transmitting and receiving unit fortransmitting and receiving an ultrasonic wave and a light transmittingand receiving unit for transmitting and receiving light are arranged,the ultrasonic wave transmitting and receiving unit being spaced fromthe light transmitting and receiving unit in an axial direction by anaxial distance L [mm], wherein an ultrasonic wave and light aretransmitted while the transmitting and receiving unit rotates, wherein,during operation of the probe, a reflected wave and a reflected lightare transmitted to an operation control apparatus of an imagingapparatus for diagnosis which uses the reflected wave received by theultrasonic wave transmitting and receiving unit from a biological tissueand the reflected light received by the light transmitting and receivingunit from a biological tissue to generate an ultrasonic wave tomographicimage and a light tomographic image of the biological tissue in an axialdirection, while the probe moves inside a body lumen in the axialdirection, the ultrasonic wave transmitting and receiving unit and thelight transmitting and receiving unit being arranged relative to oneanother such that an angular difference θ [degrees] other than 0° existsbetween the ultrasonic wave transmitting and receiving unit and thelight transmitting and receiving unit in an azimuth angle direction, arotary drive connected to the transmitting and receiving unit to rotatethe transmitting and receiving unit at a rotary velocity ω [r/s], alinear drive connected to the transmitting and receiving unit to movethe transmitting and receiving unit in the axial direction at a movementvelocity V [mm/s], the rotary drive being controlled so that the angulardifference θ [degrees] is directly proportional to the distance L [mm]in the axial direction and to the rotary velocity ω [r/s] of thetransmitting and receiving unit, and the rotary drive and the lineardrive being controlled so that the angular difference θ [degrees]between the ultrasonic wave transmitting and receiving unit and thelight transmitting and receiving unit in the azimuth angle direction isinversely proportional to the movement velocity V [mm/s] of thetransmitting and receiving unit in the axial direction.
 2. The probeaccording to claim 1, wherein the ultrasonic wave transmitting andreceiving unit and the light transmitting and receiving unit arearranged such that the distance L [mm] between the position of theultrasonic wave transmitting and receiving unit in the axial directionand the position of the light transmitting and receiving unit in theaxial direction, and the angular difference θ [degrees] between theazimuth angle directions of the ultrasonic wave transmitting andreceiving unit and the light transmitting and receiving unit satisfy arelationship of L=V/ω×θ/360 when having the rotary velocity ω [r/s] ofthe transmitting and receiving unit and the movement velocity V [mm/s]of the transmitting and receiving unit in the axial direction.
 3. Theprobe according to claim 2, wherein the angular difference θ is smallerthan 360°.
 4. The probe according to claim 3, wherein a differentialtime between a timing the ultrasonic wave transmitting and receivingunit performs scanning of a position inside the body lumen and a timingthe light transmitting and receiving unit performs scanning of the sameposition inside the body lumen is equal to or smaller than 10 msec. 5.The probe according to claim 4, wherein the distance L [mm] is equal toor shorter than 150 [μm].
 6. The probe according to claim 1, wherein anelevation angle of a transmit direction of the ultrasonic wave from theultrasonic wave transmitting and receiving unit and a transmit directionof the light from the light transmitting and receiving unit with respectto the axial direction is substantially 90°.
 7. An imaging apparatus fordiagnosis which generates an ultrasonic wave tomographic image and alight tomographic image using the reflected wave and the reflected lightwhich are transmitted from the probe according to claim 1, wherein eachframe of the ultrasonic wave tomographic image and the light tomographicimage is constructed using line data which is generated based on thereflected wave and the reflected light acquired when the ultrasonic wavetransmitting and receiving unit and the light transmitting and receivingunit respectively perform scanning of an identical scanning position. 8.A probe comprising: a rotatable transmitting and receiving unit in whichan ultrasonic wave transmitting and receiving unit for transmitting andreceiving an ultrasonic wave and a light transmitting and receiving unitfor transmitting and receiving light are arranged, a rotary driveconnected to the transmitting and receiving unit to rotate thetransmitting and receiving unit at a rotary velocity ω [r/s], a lineardrive connected to the transmitting and receiving unit to move thetransmitting and receiving unit in the axial direction at a movementvelocity V [mm/s], the ultrasonic wave transmitting and receiving unitbeing configured to emit an ultrasonic wave while the transmitting andreceiving unit rotates and moves in the axial direction, and the lighttransmitting and receiving unit being configured to emit light while thetransmitting and receiving unit rotates and moves in the axialdirection, the ultrasonic wave transmitting and receiving unit and thelight transmitting and receiving unit being arranged relative to oneanother such that an angular difference θ [degrees] other than 0° existsbetween the ultrasonic wave transmitting and receiving unit and thelight transmitting and receiving unit in an azimuth angel direction, areflected wave and a reflected light being transmitted to an operationcontrol apparatus of an imaging apparatus for diagnosis which uses thereflected wave received by the ultrasonic wave transmitting andreceiving unit from a biological tissue and the reflected light receivedby the light transmitting and receiving unit from the biological tissueto generate an ultrasonic wave tomographic image and a light tomographicimage of the biological tissue in an axial direction, while the probemoves inside a body lumen in the axial direction, and the ultrasonicwave transmitting and receiving unit and the light transmitting andreceiving unit being arranged along the axial direction, and the rotarydrive and the linear drive being controlled so that a value of V/ω×θ/360is smaller than 600 [μm].
 9. The probe according to claim 1, wherein anangle between the axial direction and an ultrasonic wave transmitdirection is substantially equivalent to an angle between the axialdirection and a light transmit direction.
 10. The probe according toclaim 8, wherein an angle between the axial direction and an ultrasonicwave transmit direction is substantially equivalent to an angle betweenthe axial direction and a light transmit direction.
 11. The probeaccording to claim 8, wherein the angular difference θ is smaller than360°, and the distance L [mm] is equal to or shorter than 150 [μm]. 12.The probe according to claim 8, wherein a differential time between atiming the ultrasonic wave transmitting and receiving unit performsscanning of a position inside the body lumen and a timing the lighttransmitting and receiving unit performs scanning of the same positioninside the body lumen is equal to or smaller than 10 msec.
 13. The probeaccording to claim 8, wherein an elevation angle of a transmit directionof the ultrasonic wave from the ultrasonic wave transmitting andreceiving unit and a transmit direction of the light from the lighttransmitting and receiving unit with respect to the axial direction issubstantially 90°.
 14. An imaging apparatus for diagnosis comprising: aprobe unit including a rotatable transmitting and receiving unit; thetransmitting and receiving unit including i) an ultrasonic wavetransmitting and receiving unit that performs ultrasonic wavetransmission and reception, and ii) an optical transmitting andreceiving unit that performs light transmission and reception; theultrasonic wave transmitting and receiving unit being spaced from thelight transmitting and receiving unit in an axial direction by an axialdistance L [mm]; a rotary drive connected to the transmitting andreceiving unit to rotate the transmitting and receiving unit at a rotaryvelocity ω [r/s]; a linear drive connected to the transmitting andreceiving unit to move the transmitting and receiving unit in the axialdirection at a movement velocity V [mm/s]; an operation controlapparatus; the ultrasonic wave transmitting and receiving unit beingconfigured to emit an ultrasonic wave while the transmitting andreceiving unit rotates and moves in the axial direction, and the lighttransmitting and receiving unit being configured to emit light while thetransmitting and receiving unit rotates and moves in the axialdirection; a reflected wave and a reflected light being transmitted tothe operation control apparatus, the operation control apparatus usingthe reflected wave received by the ultrasonic wave transmitting andreceiving unit from a biological tissue to generate an ultrasonic wavetomographic image, and the reflected light received by the lighttransmitting and receiving unit from the biological tissue to generate alight tomographic image of the biological tissue in an axial direction;the ultrasonic wave transmitting and receiving unit and the lighttransmitting and receiving unit being arranged relative to one anothersuch that an angular difference θ [degrees] other than 0° exists betweenthe ultrasonic wave transmitting and receiving unit and the lighttransmitting and receiving unit in an azimuth angle direction, therotary drive being configured to rotate the transmitting and receivingunit so that the angular difference θ [degrees] is directly proportionalto i) the distance L [mm] in the axial direction and ii) the rotaryvelocity ω [r/s] of the transmitting and receiving unit; and the lineardrive being configured to move the transmitting and receiving unit inthe axial direction so that the angular difference θ [degrees] isinversely proportional to the movement velocity V [mm/s] of thetransmitting and receiving unit in the axial direction.
 15. Thetomographic image generation device according to claim 14, wherein avalue of V/ω×θ/360 is smaller than 600 [μm].
 16. A method comprising:introducing a probe unit of an imaging apparatus into a blood vessel,the probe unit comprising: a transmitting and receiving unit comprisedof an ultrasonic wave transmitting and receiving unit that performsultrasonic wave transmission and reception; an optical transmitting andreceiving unit that performs light transmission and reception; theultrasonic wave transmitting and receiving unit being spaced apart in anaxial direction from the light transmitting and receiving unit by anaxial distance L [mm]; the ultrasonic wave transmitting and receivingunit being rotationally offset from the light transmitting and receivingunit at an angular difference θ [degrees] in an azimuth angle direction;rotating the transmitting and receiving unit at a rotary velocity ω[r/s] and moving the transmitting and receiving unit at a movementvelocity V [mm/s] in the axial direction while also transmitting boththe ultrasonic wave and the light toward biological tissue in the bloodvessel; the ultrasonic wave transmitting and receiving unit receivingthe ultrasonic wave reflected from the biological tissue in the bloodvessel, and the light transmitting and receiving unit receiving thelight reflected from the biological tissue in the blood vessel; thereflected ultrasonic wave being used to generate an ultrasonic wavetomographic image in the axial direction, and the reflected light beingused to generate a light tomographic image of the biological tissue inthe axial direction; and a value of V/ω×θ/360 is smaller than 600 [μm].17. The method according to claim 16, wherein L=V/ω×θ/360.